Between the early 1800s and the early 1990s, most bowling balls were made of three-piece construction. A small amount of dense material was poured into spherical core mold to create a pancake-like core. Then the remainder of the core mold was filled with a less-dense core material. Finally, the core was centered in a mold and a layer about 1 in (2.54 cm) thick of coverstock was poured around it. Since being pioneered by manufacturer Faball Inc. in the early 1990s, a two-piece construction method has become more popular.
Making the core
1 For the particular model of ball being manufactured, a mold is formed to the core shape developed during the computerized design process. The appropriate material is poured into the core mold and allowed to harden. The solid core is removed from its mold.
2 A second step may be necessary to finish the core. For example, some ceramic cores are fired in a kiln. A compound core may be formed by inserting the first core into a second mold and pouring material of a different density around all or part of it.
Forming the shell
3 The finished core is placed inside a spherical mold called the coverstock
Some examples of bowling bowl core shapes are lightbulb, spherical, and elliptical. Combination cores are made by enclosing a core of one shape and density within a second core of another shape and density. The main core may be supplemented by adding a collar or weight block to the core or by embedding small counterweights separately in the interior of the ball
Some examples of bowling bowl core shapes are lightbulb, spherical, and elliptical. Combination cores are made by enclosing a core of one shape and density within a second core of another shape and density. The main core may be supplemented by adding a collar or weight block to the core or by embedding small counterweights separately in the interior of the ball
mold. The core is attached to a pin that projects inward from the shell of the mold. The pin holds the core in the correct position. If the pin points toward the center of the mold, the core is said to be pin in; if it is tilted away from the center, the core is pin out.
4 The coverstock material is poured into the mold, encasing the core, and is allowed to harden. The thickness of the coverstock may be as little as 1 in (2.54 cm) or as much as 2 in (5.08 cm), depending on the design of the particular ball.
Filling the gaps
5 When the ball is removed from the coverstock mold, there is a hole where the core-holding pin had been. A plastic dowel is inserted into the hole and cemented in place. The pin is a different color than the coverstock. After the ball has been purchased, the pin will be used as a guide for positioning the finger holes to take advantage of the core design.
6 Fill material is added to the logo imprint that was molded into the ball. This may be the same color as the pin, or it may be a different color. The logo is located at the top of the ball, that is, above its center of gravity.
Finishing
7 The ball is finished to the proper size specification by turning it on a lathe and shaving off enough coverstock to achieve the right shape or it may be done on a centerless grinder that scours the ball into the desired size and roundness.
8 Finally, the surface of the ball is finished to the desired texture. It is sanded to either a matte finish or to an appropriate degree of polish, indicated by the roughness of the sanding material (generally ranging from 240-600 grit).
9 The ball is boxed and shipped to the company's distributor.
Making the core
1 For the particular model of ball being manufactured, a mold is formed to the core shape developed during the computerized design process. The appropriate material is poured into the core mold and allowed to harden. The solid core is removed from its mold.
2 A second step may be necessary to finish the core. For example, some ceramic cores are fired in a kiln. A compound core may be formed by inserting the first core into a second mold and pouring material of a different density around all or part of it.
Forming the shell
3 The finished core is placed inside a spherical mold called the coverstock
Some examples of bowling bowl core shapes are lightbulb, spherical, and elliptical. Combination cores are made by enclosing a core of one shape and density within a second core of another shape and density. The main core may be supplemented by adding a collar or weight block to the core or by embedding small counterweights separately in the interior of the ball
Some examples of bowling bowl core shapes are lightbulb, spherical, and elliptical. Combination cores are made by enclosing a core of one shape and density within a second core of another shape and density. The main core may be supplemented by adding a collar or weight block to the core or by embedding small counterweights separately in the interior of the ball
mold. The core is attached to a pin that projects inward from the shell of the mold. The pin holds the core in the correct position. If the pin points toward the center of the mold, the core is said to be pin in; if it is tilted away from the center, the core is pin out.
4 The coverstock material is poured into the mold, encasing the core, and is allowed to harden. The thickness of the coverstock may be as little as 1 in (2.54 cm) or as much as 2 in (5.08 cm), depending on the design of the particular ball.
Filling the gaps
5 When the ball is removed from the coverstock mold, there is a hole where the core-holding pin had been. A plastic dowel is inserted into the hole and cemented in place. The pin is a different color than the coverstock. After the ball has been purchased, the pin will be used as a guide for positioning the finger holes to take advantage of the core design.
6 Fill material is added to the logo imprint that was molded into the ball. This may be the same color as the pin, or it may be a different color. The logo is located at the top of the ball, that is, above its center of gravity.
Finishing
7 The ball is finished to the proper size specification by turning it on a lathe and shaving off enough coverstock to achieve the right shape or it may be done on a centerless grinder that scours the ball into the desired size and roundness.
8 Finally, the surface of the ball is finished to the desired texture. It is sanded to either a matte finish or to an appropriate degree of polish, indicated by the roughness of the sanding material (generally ranging from 240-600 grit).
9 The ball is boxed and shipped to the company's distributor.
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